/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.feilong.lib.compress.archivers.zip;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.zip.ZipException;

/**
 * Base class for all PKWare strong crypto extra headers.
 *
 * <p>
 * This base class acts as a marker so you know you can ignore all
 * extra fields that extend this class if you are not interested in
 * the meta data of PKWare strong encryption.
 * </p>
 *
 * <b>Algorithm IDs</b> - integer identifier of the encryption algorithm from
 * the following range
 *
 * <ul>
 * <li>0x6601 - DES</li>
 * <li>0x6602 - RC2 (version needed to extract &lt; 5.2)</li>
 * <li>0x6603 - 3DES 168</li>
 * <li>0x6609 - 3DES 112</li>
 * <li>0x660E - AES 128</li>
 * <li>0x660F - AES 192</li>
 * <li>0x6610 - AES 256</li>
 * <li>0x6702 - RC2 (version needed to extract &gt;= 5.2)</li>
 * <li>0x6720 - Blowfish</li>
 * <li>0x6721 - Twofish</li>
 * <li>0x6801 - RC4</li>
 * <li>0xFFFF - Unknown algorithm</li>
 * </ul>
 *
 * <b>Hash Algorithms</b> - integer identifier of the hash algorithm from the
 * following range
 *
 * <ul>
 * <li>0x0000 - none</li>
 * <li>0x0001 - CRC32</li>
 * <li>0x8003 - MD5</li>
 * <li>0x8004 - SHA1</li>
 * <li>0x8007 - RIPEMD160</li>
 * <li>0x800C - SHA256</li>
 * <li>0x800D - SHA384</li>
 * <li>0x800E - SHA512</li>
 * </ul>
 *
 * @since 1.11
 */
public abstract class PKWareExtraHeader implements ZipExtraField{

    private final ZipShort headerId;

    /**
     * Extra field data in local file data - without Header-ID or length
     * specifier.
     */
    private byte[]         localData;

    /**
     * Extra field data in central directory - without Header-ID or length
     * specifier.
     */
    private byte[]         centralData;

    protected PKWareExtraHeader(final ZipShort headerId){
        this.headerId = headerId;
    }

    /**
     * Get the header id.
     *
     * @return the header id
     */
    @Override
    public ZipShort getHeaderId(){
        return headerId;
    }

    /**
     * Set the extra field data in the local file data - without Header-ID or
     * length specifier.
     *
     * @param data
     *            the field data to use
     */
    public void setLocalFileDataData(final byte[] data){
        localData = ZipUtil.copy(data);
    }

    /**
     * Get the length of the local data.
     *
     * @return the length of the local data
     */
    @Override
    public ZipShort getLocalFileDataLength(){
        return new ZipShort(localData != null ? localData.length : 0);
    }

    /**
     * Get the local data.
     *
     * @return the local data
     */
    @Override
    public byte[] getLocalFileDataData(){
        return ZipUtil.copy(localData);
    }

    /**
     * Set the extra field data in central directory.
     *
     * @param data
     *            the data to use
     */
    public void setCentralDirectoryData(final byte[] data){
        centralData = ZipUtil.copy(data);
    }

    /**
     * Get the central data length. If there is no central data, get the local
     * file data length.
     *
     * @return the central data length
     */
    @Override
    public ZipShort getCentralDirectoryLength(){
        if (centralData != null){
            return new ZipShort(centralData.length);
        }
        return getLocalFileDataLength();
    }

    /**
     * Get the central data.
     *
     * @return the central data if present, else return the local file data
     */
    @Override
    public byte[] getCentralDirectoryData(){
        if (centralData != null){
            return ZipUtil.copy(centralData);
        }
        return getLocalFileDataData();
    }

    /**
     * @param data
     *            the array of bytes.
     * @param offset
     *            the source location in the data array.
     * @param length
     *            the number of bytes to use in the data array.
     * @see ZipExtraField#parseFromLocalFileData(byte[], int, int)
     */
    @Override
    public void parseFromLocalFileData(final byte[] data,final int offset,final int length) throws ZipException{
        setLocalFileDataData(Arrays.copyOfRange(data, offset, offset + length));
    }

    /**
     * @param data
     *            the array of bytes.
     * @param offset
     *            the source location in the data array.
     * @param length
     *            the number of bytes to use in the data array.
     * @see ZipExtraField#parseFromCentralDirectoryData(byte[], int, int)
     */
    @Override
    public void parseFromCentralDirectoryData(final byte[] data,final int offset,final int length) throws ZipException{
        final byte[] tmp = Arrays.copyOfRange(data, offset, offset + length);
        setCentralDirectoryData(tmp);
        if (localData == null){
            setLocalFileDataData(tmp);
        }
    }

    protected final void assertMinimalLength(final int minimum,final int length) throws ZipException{
        if (length < minimum){
            throw new ZipException(getClass().getName() + " is too short, only " + length + " bytes, expected at least " + minimum);
        }
    }

    /**
     * Encryption algorithm.
     *
     * @since 1.11
     */
    public enum EncryptionAlgorithm{

        DES(0x6601), RC2pre52(0x6602), TripleDES168(0x6603), TripleDES192(0x6609), AES128(0x660E), AES192(0x660F), AES256(0x6610), RC2(
                        0x6702), RC4(0x6801), UNKNOWN(0xFFFF);

        private final int                                      code;

        private static final Map<Integer, EncryptionAlgorithm> codeToEnum;

        static{
            final Map<Integer, EncryptionAlgorithm> cte = new HashMap<>();
            for (final EncryptionAlgorithm method : values()){
                cte.put(method.getCode(), method);
            }
            codeToEnum = Collections.unmodifiableMap(cte);
        }

        /**
         * private constructor for enum style class.
         */
        EncryptionAlgorithm(final int code){
            this.code = code;
        }

        /**
         * the algorithm id.
         *
         * @return the PKWare AlgorithmId
         */
        public int getCode(){
            return code;
        }

        /**
         * Returns the EncryptionAlgorithm for the given code or null if the
         * method is not known.
         * 
         * @param code
         *            the code of the algorithm
         * @return the EncryptionAlgorithm for the given code or null
         *         if the method is not known
         */
        public static EncryptionAlgorithm getAlgorithmByCode(final int code){
            return codeToEnum.get(code);
        }
    }

    /**
     * Hash Algorithm
     *
     * @since 1.11
     */
    public enum HashAlgorithm{

        NONE(0), CRC32(1), MD5(0x8003), SHA1(0x8004), RIPEND160(0x8007), SHA256(0x800C), SHA384(0x800D), SHA512(0x800E);

        private final int                                code;

        private static final Map<Integer, HashAlgorithm> codeToEnum;

        static{
            final Map<Integer, HashAlgorithm> cte = new HashMap<>();
            for (final HashAlgorithm method : values()){
                cte.put(method.getCode(), method);
            }
            codeToEnum = Collections.unmodifiableMap(cte);
        }

        /**
         * private constructor for enum style class.
         */
        HashAlgorithm(final int code){
            this.code = code;
        }

        /**
         * the hash algorithm ID.
         *
         * @return the PKWare hashAlg
         */
        public int getCode(){
            return code;
        }

        /**
         * Returns the HashAlgorithm for the given code or null if the method is
         * not known.
         * 
         * @param code
         *            the code of the algorithm
         * @return the HashAlgorithm for the given code or null
         *         if the method is not known
         */
        public static HashAlgorithm getAlgorithmByCode(final int code){
            return codeToEnum.get(code);
        }
    }
}
